Making methylthiophenol-ortho-carboxylic acid.



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BENNO HOMOLKA, OF FRANKFORT-OlV-THE-MAIN, AND RICHARD WELDE, OF HGCHST-ON- THE-MAIN, GERMANY, ASSIGNORS TO FARBWERKE VORM.-MEISTER LUOIUS &-BRlilNING, OF HOCHSTQN-THE-MAIN, GERMANY, A CORPO RATIONOF GERMANY.

MAKING METHYLTHIOPHENOL-QRTHO-CARBOXYLIC ACID.

To all whom it may concern:

Be it known that we, BENNO HOMOLKA, Ph. DI, and RICHARD WELDE, Ph. D., chemists, citizens of the Empire of Germany, and residing at Frankfort on the Main and Hochst-on-the-Main, Germany, respectively, have invented certain new and useful Improvements in Making. Methylthiophenol- Ortho-CarboxylicAcids, of which the following is a specification;

We have found that methylthiophenolorthocarboxylic acids having the general uct of the -reaction of diazoti'zed ortho-.

alninobenzoic acids on soluble metal ,sulfids orsulfhydrates or it may be an ethereal compound ,or ether-like compounds of thiothio-carbonates (Xanthogenates) phenol-ortho-carboxylic acids, such, for instance, as the readily obtainable ethereal having the generalformula:

' coon 1 Wherein .R means an alkyl, and R' an aromatic residue or it may be thio-cyanogen compounds having the general formulaa {coon 1 $4: 2 1 wherein Rlrneansan aromatic residue or disulfids having the general formula r coon (i) 1 H000 Specification of Letters;Patent.

Application filed February 5, 1907. Serial No. 355,873.

Patented May 2c, 1908".

(Specimens.)

to the following equation:

COONa 2 OCH-3 It is preferable to expel the methyl methyl thiophenol-ortho-carboxylate by; means of steam and to precipitate from the residue the methylthio ,henol-ortho-carboxylic acid by' adding hy rochloric acid. By heating. the methyl methylthiophenol-ortho-carboxylate with aqueous caustic alkalies and by subsequently precipitating. by adding a mineral acid, the free methylthiophenol-ortho-carboxylic acid may beobtained in the form-of white flakes soluble in water Witheat difficulty. The acid is readily ,solub e in hotalcohol and hot acetic acid and se arates-as crystals from the hot saturated so utions-on cooling. It melts at 168'169 C.

Example II. The solution of ortho-diazo- .benzoic acid ob tained bydiazotizing 139 parts of anthranilic acid, .of 98.3 per cent.

strength, is slowly run into a solution of 250 parts by weight of sodium sulfid (Na SQaq) and 300 parts'b'y Weight of sodium methyl sulfate of 46 per cent; strength, preferably after neutralization withsodium carbonate, while stirring, at 60-7 0 C., the Whole being finally heated for some time to ebullition.-

The niethylthiophenol ortho carboxylic acid is isolated from the roduct of reaction by precipitating by addition of a mineral acid; it may be purified by recrystallization.

Example III. 242 parts by-weight of an ethereal thio-carbonate of benzoic acid together with 125 parts by Weight of caustic alkali per cent. strength) are dissolved in about 800 parts of alcohol (70 per cent. strength), and 300 parts by weight of methyl iodid or the equivalent quantity of another methyl halid are added, the whole being heated to about 90100 C. for some hours.-

The volatile products arethen distilled away and the ethereal methylthiophenol-orthocarboxy late is driven over with steam. Analogous to Example I the methylthio-phenoL. ortho-carboxylic acid is obtained by hydroly sis ortho-thiocyano-benzoic acid are heated for about three hours in a reflux apparatus with 600 par-ts by weight of soda-lye of 27 Be.

specific gravity and 585 parts by weight of sodium methylsulfate (of 46 per cent. strength). The methylthiophenol orthocarboxylic acid is isolated by acidifying with -a mineral acid and is purified, if necessary,

by re-crystallization. 7

Example V. 15.3 parts by weight of phenyldithio ortho ortho dicarboxylic acid, 8.0 parts by weight of caustic soda and 58 parts by weight of sodium methylsulfate (of 46 per cent. strength) are dissolved in 4.050

parts of water and the solution is heated to ebullition in a reflux apparatus for about 5 hours, Small quantities of methyLmethylthiophenol-ortho-carboxylate are distilled from the product by steam, and from the residue the methylthiophenol-ortho-carboxylic acid is precipitated by adding a dilute mineral acid.

According to the methods indicated in Ex- Example IV. 179 parts by weight of I seaoio agents, and red dyestuffs when heated with fuming sulfuric acid. v

Having now described our invention, what we claim is I I 1. As a new product, the methylthiophenol-o-carboxylic acid having the general formula:

coorr 1 s-on 2 wherein R means an aromatic residue and whereln 'the hydrogen-atom of the carboxylic group may be replaced by an alkyl- I radical, being colorless, soluble in alkalies; little soluble in water, readily soluble in altcohol, methyl alcohol and glacial acetic acid,

yielding, when heated with alkaline condensing agents, alpha oxy thionaphthene and a dyestufi when heated with fuming sulfuric acid.

2. The process of making methylthiophenol-o-carboxylic acids, as set forth, which consists in causing methylating agents to act on alkaline solutions of thiophenol-o-carboxylic acids having the general formula:

coon 1 sH 2 wherein R means an aromatic residue and wherein the hydrogen atom of the carboxylic group may be replaced by an alkyl radical.

In testimony, that We claim the foregoing as our invention, we have signed our names in presence of two subscribing witnesses.

- BENNO HOMOLKA.

RIGHARD WELDE.

Witnesses JEAN GRUND, CARL GRUND. 

